Extend enable-lookalike-url-navigation-suggestions tp M84

It's needed for the iOS version of the lookalike interstitial.

Change-Id: Iee91e52696cbb68b119c155151e4028af3c3d066
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067675Reviewed-by: Livvie Lin <livvielin@chromium.org>
Commit-Queue: Mustafa Emre Acer <meacer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743381}

chrome/browser/flag-metadata.json

@@ -1543,7 +1543,7 @@
   {
     "name": "enable-lookalike-url-navigation-suggestions",
     "owners": [ "jdeblasio", "meacer", "livvielin" ],
-    "expiry_milestone": 81
+    "expiry_milestone": 84
   },
   {
     "name": "enable-mark-http-as",